Media AND Presenters

QuickTime understands media through the pairing of media data and a metadata object that describes the format and characteristics of that media data. This media data can exist either on some external storage device or in memory. The media data can further be stored in the movie itself or can exist in other files, either local or remote. The metadata object that describes the format of the media data is known as a SampleDescription. There are various extensions to the base-level SampleDescription that are customized to contain information about specific media types (e.g., ImageDescription for image data).

This section discusses the following topics:

• retrieving media data and QuickTime's use of this complex and powerful capability, particularly with the introduction of multimedia streaming
• using presenters to express an object that renders media data loaded into or residing in memory
• the ImagePresenter class, which is the principal class in the QuickTime for Java API that presents such image data